Authorities are hoping to find new clues in the Boston Marathon bombing case by poring over a laptop belonging to one of the suspects and learning what the other told his wife in a phone call days after the blast, sources told ABC News.

Robert Stahl, an attorney for a friend of bombing suspect Dzhokhar Tsarnaev, said his client had taken Dzhokhar's laptop from his room but turned it over to the FBI "the very first time" agents came to see him late Friday, four days after the bombing.

Stahl's client, 19-year-old Dias Kadyrbayev, was charged along with another 19-year-old friend with conspiracy to obstruct justice for taking the laptop and allegedly trying to dump a backpack full of fireworks -- which had been emptied of their powder -- also belonging to Dzhokhar after they realized Dzhokhar was involved in the bombing. After the teens' court appearance Wednesday, Stahl denied his client knew Dzhokhar was involved in the attack at the time and said Kadyrbayev did not think the items were of evidentiary value.

A law enforcement official also told ABC News today that the FBI is seeking to find out what the other bombing suspect, Dzhokhar's older brother Tamerlan Tsarnaev, told his wife in a phone call shortly after the FBI released his photo to the public three days after the attack. The official said only the woman, Katherine Russell, knows the content of the conversation.

Russell's attorney said in a statement Tuesday that she was providing "as much assistance to the investigation as she can."

Tamerlan and Dzhokhar Tsarnaev are accused of planting two bombs near the finish line of the Boston Marathon on April 15. When the bombs exploded, three people were killed and more than 260 others were injured. Three days after the bombing the FBI released surveillance images of the suspects, who they had not yet identified, in hopes the public may be able to track them down. Hours later, Tamerlan was killed in a firefight with police. Dzhokhar escaped for a while but was injured and eventually caught on April 19.

Terrel Harris, a spokesperson for the Massachusetts Office of the Chief Medical Examiner, told ABC News that Tamerlan's body will be released from his office today to Tamerlan's family.

Wednesday authorities arrested three 19-year-old friends of Dzhokhar's: Dias Kadyrbayev and Azamat Tazhayakov, both students originally from Kazakhstan, and American Robel Phillipos. In addition to the conspiracy to obstruct charges against Kadyrbayev and Tazhayakov, Phillipos is charged with lying to federal investigators.

Attorneys for the Kazakh students said their clients had nothing to do with the bombings, and they disputed parts of the criminal complaint against their clients. An attorney for Phillipos reportedly said his client was not connected to the bombing or to the Kazakh students' actions and downplayed his client's alleged lies as "misrepresentations."

Charging documents filed Wednesday against Dzhokhar's friends revealed new details in the case, including an exchange that took place a month before the attack in which Dzhokhar allegedly bragged that he knew how to build explosive devices. Dzhokhar also allegedly responded to one of his friends who asked if was the suspect shown in FBI photos with "LOL."